| 초록 |
ALE provides a method to etch material of thin films with atomic level precision. Especially, thermal ALE that can isotopically etch complex 3D nanostructures, require spontaneous surface chemical reactions to generate volatile species from the substrate. To date, most known chemistry for thermal ALE of Al2O3 involve a fluorination step by HF or SF6, and then etching AlF3 by another compound that reacts with AlF3 such as Al(CH3)3. Compared to the fluorination mechanism of the substrate using HF, few reports have studied the second ligand-exchange reactions generating volatile etch products. In a previous study, it was observed that the volatile etch products are in dimeric forms. Also, the etchants can exist in monomeric or dimeric forms, which can affect its reactivity. In this work, we investigated the chemical mechanism of possible group-13 containing compounds for thermal etching of AlF3 via DFT calculations. Interestingly, the reactivity of the precursor with surface AlF3 is expected to be related to the dimerization energy of the etchants themselves. Based on our results, we find several viable potential compounds that can thermally etch the AlF3 layer from the surface. |
